Polyaniline/CeO2 nanocomposites as corrosion inhibitors for improving the corrosive performance of epoxy coating on carbon steel in 3.5% NaCl solution

Polyaniline/cerium dioxide (PANI/CeO₂) nanocomposite (NPs) was synthesized by in situ polymerization of aniline in the presence of CeO₂ NPs. Various analytical facilities, i.e., powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM), were utilized to characterize the synthesized CeO₂ and PANI/CeO₂ NPs. The coatings prepared from the synthesized PANI/CeO₂ NPs exhibited excellent corrosion resistance that was superior to epoxy coatings added with PANI in NaCl solution. The exceptional improvement of corrosion protection performance of the PANI/CeO₂ /epoxy coatings is associated with the synergetic protection of the enhancement of the protective barrier due to the role of CeO₂ NPs and PANI against the diffusion of aggressive ions (e.g., Cl⁻) and the improvement of self-healing protection attributed to the redox behavior of PANI. Thus, the hybrid PANI/CeO₂ NPs are considered as the best route to enhance the protection performance of the epoxy coatings on carbon steel.